The NMR (available through Coflein) describes the circle, alluding to the legend of Fowler the giant:
A degraded possible stone circle, 13m in diameter, represented by four stones, one of them erect. the eponymous stone, named for a local giant (but see Nprn305882) lies within the circle.
The record referred to as Nprn305882 is the arm chair itself (strangely not available through Coflein).